Conventionally, ink jet printers employing an ink jet method are widely used (for example, internet URL http://www.mimaki.co.jp.). In the ink jet printer, ink droplets are discharged from nozzles of ink jet heads so that printing is performed. Further, a driving element for discharging ink droplets from each nozzle is provided on each position of each nozzle in the ink jet head. For example, a piezoelectric element is widely used as such a driving element.